Waste gas burner



Aug. 13, 1957 o. F. CAMPBELL ETAL WASTE GAS BURNER 2 Sheets-Sheet lFiled March l5, 1950 INVENTORs Aug. 13, 1957 o. F. CAMPBELL ETAL2,802,521 l WASTE GAS BURNER Filed March l5, 1950 Sheets-Sheet 2 Riff/-ff 20 E19@- ATTORNEYS United States Patent 2,802,521 A WASTE GAS BURNERDliver F. Campbell and William H. Decker, Whiting, Ind., assignors toSinclair Refining Company, New

York, N. Y., `a corporation of Maine Application March 15, 1950, SerialNo. 149,797 11 Claims. (Cl. 158-115) Our invention relates to animproved emergency waste gastlare and 'a safe and reliable m-ethod forburning waste combustible gases of widely Varying he-at content atwidely varying rates of dlow. It particularly provides economical andreliable means for the safe and smokeless combustion of large quantitiesof petroleum refinery gases during emergency or shutdown periods in therenery.

`Refinery evolution and the increasing attention of the publicauthorities to the problem of atmospheric polution have combined to makethe safe and effec-tive disposal of waste refinery gases significant.The trend in refineries `has been toward lar-ger units increasing gasproduction, toward new processes `such .as catalytic cracking producinggreater volumes of light gases and toward more process-es handling andemploying light gases. At the same time the dangers of smog and gaseouscontamination ofthe atmosphere to health and the annoy-` ance of lsmokein the lvicinity of cities have Aattracted the attention of publicauthorities and in some eases have invi-ted restrictive regulation. Theproblem of providing for adequate disposal of refinery gases undervarying renery conditions is a severe one because gas storage spacecannot economically be provi-ded for all contingenices or even for peakproduction levels. lf the waste gases are to be burned, they must beburned without substantial generation of smoke and without endangeringrenery equipment orl personnel. A flare designed 4to burn waste ygasesmust be capable of handling quantities of gas varying from.substantially Zero flow to rates las high as 250,000 cubic` `feet perhour. The gas may vary in heat content `from 500 iB. t. u. to as high as2,500 \B. t. u. per cubic foot and may contain relatively highpercentages of We-t fractions. The gas may be at pressures ranging fromIapproximately atmospheric to as high as 25 p. s. i. g. A useful wastegas flare must "be capable of handling gases under these widely varyingconditionsy and must be capable of burning such gases without generatingappreciable quantities of smoke. Such a are' also must be low in costand simple to construct -ande-mustbe'extremely rugged to stand up undersustainedV periods of highv gas combustion rates. llt must besubstantially fool-proof in operation and should be -provided withpositive typeignition pilot burners which can be operated remotely.

According to Vour invention, we provide a bu-rner assembly situated forthe sake of safety lat the end of an elevated gas-pipe of large section.The burner assembly comprises a cap plate supported .at a distance fromthe end of thepipe so as to provide la peripheral gas exitjof' greaterarea than the cross-sectionalA area of the pipe and further -comprises aplurality of steam jets surrounding theA gas exit. We have found thatthe available energy contained in the high pressure steam providesadequate mixing of the gases to be burned with combustion :air so as t-oobtain Isultastantially smokeless p combustion by ejecting the steam athigh pressure :around the gas exit. Preferably, the ejection meanscomprises a .steam ring which isperforated on its upper side so, l,

las to fact as an aspirating device. The ejected steam then provides thenecessary quantities of air and effects turbu- 'lent fmxing offthe air"with the gases to *beV burned so .that smokeless combustion results.

A metal shroud surrounding the burner assembly is provided to act as apartial mixing chamber. A flame arresting means is interposed in the gaspipe between the gas exit and the point of supply. A pilot burner systemwhich can be operated remotely is provided in association with theburner -assembly so as to insure positive ignition.

Our invention will be described by reference'to the accompanyingdrawings. Figure 1 represents a view of a vertical type emergency gasburner in side elevation with parts broken :away or inverted. Figure 2represents av section upon the lines 2-2 of Figure l. Figure 3represents an enlarged view of the upper portion of ,the

burner including the burner assembly partly in section along lines 3-3of Figure 4. Figure 4 represents a top plan view of the burner assembly.Figure 5 represents an enlarged View of a portion of the pilot burnerass-embly visible in Figure 3. talcen along lines 6-6 of Figure 5.

.The emergency gas burner iadvantageously' is Ia tall is supplied to thegas standpipe 10 through section 124 and through gas main 14.

A llame arrestor designed to prevent liareback of gases is situated ontop of the lstandpipe 10 and is housed in section 15. The -tlamearrester may consist of` a series of interlocking bars forming a largearea of cooling surface. A second standpipe or flare pipe 16, 25 inchesin diameter by approximately l0 feet high, is mounted on top of the amearrestor housing 15. The top of the ilarepipe 16 is capped with a flatcircular plate'17 supported ,at its periphery by steel stripsor slats18, 6 inches in lengt-h `arranged so that Ithe open 4area lbetween thesupporting strips is slightly greater than the area ofthe flare :pipe 16itself. The structure of the cap plate 17 and supporting strips 18 isbetter seen in Figures 3l an-d 4. Advantageously, the supporting slats18 of the burner assembly are set lat an `angle of `approximately 45 sothat a tangential swirling moti-on Vis imparted to the released gaseswhich will aid considerably in mixing the gases with the incoming air.The top of the capplate 17 advantageously is protected from hightemperatures by application of applastic refractory material. At theelevation of the burner end of flare pipe 16, :a steel shroud 19 ismounted by means of gusset plates 20. -As

and 'is supported by gusset plates 20. The steam ringY 21 is drilledalong its upper sur-face with seventy-two la-inch holes to provide `forthe injection ofihigh pres-` sure steam Isupplied through a 2-inch steamline 22. Steam line 22 is insulated andconnected by flexible connection23 and connection 24 to .a steam header 25. Steam flow may be controlledby tmeans of block valve 26. Advantageously iturbulent mixing ofPatented Aug. 13, 1957 Figure 6 is a sectional view- K @if thib-Vrelease gases is promoted -by drilling the injection-holes in steam ring21so that they are slanted inthe, same4 3 direction as the supportingstrips or slats 18 in the gas exit area. Y

The pilot burner assembly comprises three 4-inch pilot guide pipes27which are symmetrically varrangedraround are pipe 16 with their upperends liushv with the bottom of the Vgas exit in the burnerV assembly.The pilot guide pipes 27 are each provided with a l-inch slot 28extending its entire length and opening outwardly from the center of theburner. The details of the pilot burner assembly are better seen inFigures 3, 4, and 6. The lower end ofthe pilot guide pipes 27 is coveredby a conical steel shield 29 to protect spark igniters 30 from directflame impingement or ameradiation. Spark ig-Y niters 30 are high tensionspark plugs mounted in opposing pairs in each of the pilot guide pipes27 approximately 6 inches from the lower end. The spark igniters 30 aretied to high tension transformer boxes (not shown) and a remotelylocated push button station is provided for spark ignition. In thecenter of each of pilot guide pipes 27 is installed a single 3winch JohnZink type ST pilot burner 31. This burner is a simple air-mixing typegas jet and each pilot burner 31 is provided with a premixing chamber 32below the bottom end of each pilot guide pipe 27. The burners of pilot31 are located approximately 6 inches below the top end of the pilotguide pipes 27. Each of the three pilot burners 31 is connected throughgas supply ring 33 to a single gas supply header 34 which is providedwith a block valve 35 at the base of pipe 12 for remote operation. Inorder to provide for ignition of pilot burners 31 each of the individualpilot guide pipes 27 is supplied with three 1t-inch pipe leads 36through a header 37 and ring gas supply pipe 38, which is suppliedthrough l-inch gas line 39. Gas line 39 is provided at the base ofstandpipe 12 with a flexible connection 40 and may be controlledremotely by block valve 41. The pipe leads 36 are arranged so that theyproject through the 1-inch slot 28 in pilot guide pipes 27 and arespaced approximately equi-distant` along the length of pilot guide pipes27. o

In order to place the burner in operation, the spark igniter circuit isclosed, and the gas supply block valve 41 to pilot guide pipes 27 isopened. As soon as ignition is assured, as may be seen by ame coveringthe: entire length of pilot guide pipes 27., Vthe gas supply of blockvalve 35 to pilot burners 31 is opened. When it is evi dent that pilotburners 31 are inservice, the block valve 41 controlling thepre-'ignition gas flow to pilot guide pipes 27 is turned off. At thesame time the igniter circuit is open since there is no need to maintaincontinued exitation of the spark plug. The burner is `now ready foremergency tiring of dump gases. When daring begins, the block valve 26supplying steam to steam aspirat,

ing yring 21 is opened slowly and is adjusted so that theY rate of steamow is such as to provide `for smokeless combustion. The quantity ofsteam required is a function of the quantity of gas being burned, the B.t. u. value of the gas and the pressure head of the dump gases. If atany time during actual operation, pilot burners 31 are extinguished, theignition process is repeated. In test operation, it has been found thatthe burner may be readily ignited by employing the pilot burnersysternof our invention and that the pilot ames are stable andapparentlyunaifected by high wind or heavy rain conditions. Thus,positive ignition of the vmain dump gas stream is assured. At theinitiation of the test run, gas was released from the main refinery gasholdery 'atv a rate of about 130,000 cubic feet per hour. At the vstartno steam Vwas used and tremendousquantities of heavy black smoke wereproduced. When steam was admitted to thesteam ring, the Ysmokingcondition cleared up very quickly. Satisfactory mixing was shown by thefact that it was almost impossible to directly observe the ame, and thedame produced was excessively bright without smoke. During thetestperiod, approximately 4,200 to 4.500 pounds per. hour of 125 poundssteam wereV eme 4 I ployed for the dumping rate of 130,000 vcubic feetper hour. The gas was estimated to have a B. t. u. value ofapproximately 1,300 B.t. u.s per cubic foot. The` gas was supplied tothe burner at a pressure of only several inches of water from akwater-sealed gas holder. Our invention provides a simple, safe andreliable system for assuring smokeless combustion of refinery .gasesunder emergency dumping or waste an'ng conditionsnby utilization of theenergy content of high pressure steam or other gas to supply the desiredamount of combustion and assure turbulent admixture. .Our inventionprovides a burner and method of operation that Vassures substantiallysmokeless combustion over a wide` range of4 gas rates from substantiallyzero ow to as high as 250,000 cubic feet per hour or more. VGasesrangingin B. t. u.

content from 500 B. t. u. to 3,000 B.1t.`u. per cubicfoot. are equallywell handled, Vand operation is satisfactory over a range of a fewounces to 25 p. s.. i. g. or more.` Thus a means is providedforemergency disposalof gases in the event of emergency shutdown of acrackingunit or in the event of a sudden drop in the normall burningcapacity of the renery Yso that the refinery gas holders are overloadedand their water-seals broken through gas overflow. On the other hand,our invention provides a useful means for disposing of small amounts ofgas vented into the refinery gas system during the usual daily testingof safety valves in units such as propane solvent treating where largequantities of gas under high pressure are employed. Y

The combustion of gases according to our invention is'for all practicalpurposes instantaneous so that close adherence to existing smokeregulations is assured. Because of the simplicity of the burner, it issimple to construct at low cost. The use of high alloy materials may beavoided by the use of suitable plastic refractory matef rials since allmetal surfaces exposed to llame radiation or flame impingement may bereadily protected. The

operated remotely from any location.

commenced the steam or air or gas required could be supplied in directrelationship to theY amount of gases to be burned. Such a control valvemay be operated by pressure, by :Elow or by a combustion` control meanssuchV as a flame detectoror haze gauge. The burner requires very littleground space and may be adapted to installation on top of variousstructures, such as-large refinery stills.:

or buildings. The burner maybe locatedhoweverat grade in a horizontalposition. A number Vofsmallerunits tiring into a target Wall may beemployed. Ob-

viously a number of changes may be effected intheburner design andmethod of operation we have described. l

Forfexample, a plurality of steamrings or a plurality of steam supplypipes to the steam ring may be employed tov obtain improved mixing andpressure control. Irl-- 1 stead of a circular steam ring, a pluralityV`of individualV small venturi sections may be arranged ysyir'imetxjcallyaround the gas exit area. supplied by individual small steamsupply'lines. Also the metal shroud section surrounding the burnerassemblyY may be constructed with advantage in the formk of a large'venturi section in order to assistin supplying-air'to 'the burnerproper. Combustion air or gascould belemployed in place of the steammixing medium. .Y i K We claim: Y i i 7 1. A11r emergency gas Hare'which comprises aufeten-gv gated gas pipe; a burner assembly comprisinga'eap. plate.

The venturi sections may @be supported at a distance from the end of thepipe so as to p provide a peripheral gas exit of greater area than thecross-sectional area of the pipe, and a plurality of steam jetspositioned around said end of said pipe and directed across the path ofgas owing from said gas exit; an open ended shroud of closed side wallconstruction having a section larger than said gas pipe mountedcoaxially therewith and surrounding the burner assembly, the inner endof said shroud being positioned inwardly of the outer end of said gaspipe and the outer end of said shroud being positioned outwardly of saidcap plate; ilarne arresting means interposed in the pipe between the gasexit and the point of gas supply; means for supplying steam to saidsteam jets; and a pilot burner assembly comprising at least one openended pilot guide pipe mounted lengthwise of said gas pipe with theouter end of said guide pipe adjacent said peripheral gas exit andpositioned between said gas pipe and said steam jetsv and with the innerend of said guide pipe positioned inwardly of the inner end of saidshroud, a slot in said guide pipe extending lengthwise thereof andopening outwardly from said gas pipe, and pilot llame ignition meansmounted in said guide pipe including a pilot burner at the outer end ofsaid guide pipe, means for supplying gas to the inner end of said guidepipe, and spark ignition means at the inner end of said guide pipe forignition of gas in said guide pipe.

2. The gas liare of claim 1 in which the plurality of steam jets of theburner assembly represent a perforated ring pipe surrounding the gasexit.

3. The gas flare of claim 1 in which the cap plate is supported by aplurality of spaced slats set at an angle of approximately 45 with aplane through each slat and the axis of the gas pipe.

4. The gas flare of claim 1 in which the shroud is constructed in theform of a venturi section surrounding the burner assembly.

5. An emergency gas flare which comprises an elongated gas pipe; aburner assembly comprising a cap plate supported at a distance from theend of the pipe so as to provide a peripheral gas exit of greater areathan the cross-sectional area of the pipe and a plurality of steam jetspositioned around said end of said pipe and directed across the path ofgas llowing from said gas exit; an open ended shroud of closed side wallconstruction having a section larger than said gas pipe mountedcoaxially therewith and surrounding the burner assembly, the inner endof said shroud being positioned inwardly of the outer end of said gaspipe and the outer end of said shroud being positioned outwardly of saidcap plate; flame arresting means interposed in the pipe between the gasexit and the point of gas supply; means for supplying steam to saidsteam jets; a pilot burner assembly comprising a plurality of open endedpilot guide pipes mounted lengthwise of said gas pipe and symmetricallydisposed about said gas pipe with the outer end of each of said guidepipes adjacent said peripheral gas exit and positioned between said gaspipe and said steam jets and with the inner end of each of said guidepipes positioned inwardly of the inner end of said shroud, a slot ineach of said guide pipes extending lengthwise thereof and openingoutwardly from said gas pipe, pilot flame ignition means mounted in eachof said guide pipes including a pilot burner at the outer end of saidguide pipe, spark ignition means at the inner end of said guide pipe forignition of gas in said guide pipe, means for supplying gas to the innerend of said guide pipe, means for supplying gas intermediate the lengthof said guide pipe, and a shield mounted around the gas pipe forcovering the spark ignition means.

6. An emergency gas are which comprises a vertically elongated gasstandpipe mounted on a swivel base; flame arresting means mounted on thestandpipe; a vertically elongated flare pipe mounted on the flamearresting means; a burner assembly comprising a cap plate supportedupwardly from and transversely to the end of the flare pipe so as toprovide a peripheral gas exit of greater area than the cross-sectionalarea of the pipe and a plurality of steam jets positioned around saidend of said pipe and directed across the path of gas flowing from saidgas exit; an open ended annular shroud of a diameter larger than saidare pipe mounted coaxially therewith and surrounding the burnerassembly, the inner end of said shroud being positioned inwardly of theouter end of said gas pipe and the outer end of said shroud beingpositioned outwardly of said cap plate; means for supplying steam tosaid steam jets; and at least one open ended pilot guide pipe mountedlengthwise of said gas pipe with the outer end of said guide pipeadjacent said peripheral gas exit and positioned between said gas pipeand said steam jets and with the inner end of said guide pipe positionedinwardly of the inner end of said shroud, a slot in said guide pipeextending lengthwise thereof and opening outwardly from said gas pipe,and pilot llame ignition means mounted in said guide pipe including apilot burner at theV outer end of said guide pipe, spark ignition meansat the inner end of said guide pipe for ignition of gas in said guidepipe, means for supplying gas to the inner end of said guide pipe, andmeans for supplying gas intermediate the length of said guide pipe.

7. An emergency gas flare comprising a gas pipe for conducting wastegas; a burner assembly mounted on said gas pipe having a cap platesupported outwardly of the outer end of said gas pipe and transverselythereto to provide a peripheral gas exit of greater area than thecross-sectional area of the pipe, and aspirating means positioned at andaround said outer end of said gas pipe and directed to eject a fluidacross the path of Waste gas owing from said peripheral gas exit; and anopen ended shroud having a closed side wall forming a mixing chambersurrounding said burner assembly and said gas pipe, the inner end ofsaid shroud being positioned inwardly of the outer end of said gas pipeand the outer end of said shroud being positioned outwardly of said capplate.

8. An emergency gas are in accordance with claim 7 in which theaspirating means includes a perforated ring pipe surrounding theperipheral gas exit.

9. An emergency gas ilare in accordance with claim 7 in which the capplate is supported by a plurality of spaced slats set at an angle ofapproximately 45 with a plane passing through each slat and the axis ofthe gas pipe.

10. An emergency gas flare in accordance with claim 7 in which theshroud is constructed in the form of a Venturi section surrounding theburner assembly.

11. An emergency gas ilare in accordance with claim 7 and including apilot burner assembly comprising an open ended guide pipe mountedlengthwise of said gas pipe with its outerend adjacent said peripheralgas exit positioned within the space enclosed by said shroud and withits inner end positioned inwardly of the inner end of said shroud, apilot burner positioned at the outer end of said guide pipe, and a slotextending lengthwise of said guide plpe and opening outwardly from saidgas pipe.

References Cited in the le of this patent UNITED STATES PATENTS1,302,914 Goreau May 6, 1919 1,561,848 Green Nov. 17, 1925 1,669,463Garden May 15, 1928 2,365,102 Olds Dec. 12, 1944 2,389,027 Corbin et alNov. 13, 1945 2,460,016 Kuhn June 25, 1949 2,480,230 Elster Aug. 30,1949 2,506,922 Schellentrager et al May 9, 1950 2,537,091 Rodman et al.Ian. 9, 1951 FOREIGN PATENTS 191,309 Germany Nov. 5, 1907

